This invention relates to a method for transmitting voice information which enables the transmission of much voice information with a high efficiency.
Radio broadcasts are popular media for transmitting voice information to many anonymous people. Radio broadcasting connects several radio stations with many receivers, with each radio station monopolizing one frequency of carrier wave. A receiver can select an arbitrary radio station by tuning his radio dial to the frequency.
Voices are generated from the receiver's speaker continuously, for the receiver cannot know the substance of the earlier received voice information. He or she may miss hearing necessary information, unless he or she is listening at all times to the radio. Also, since one radio station sends various kinds of information, a choice of a broadcasting station is not equivalent to a choice of the substance of information received. It is the radio station that determines what kinds of information will be sent. Consequently, a receiver has the freedom to determine whether he will hear the radio or not and the freedom to choose a particular radio station; however, a receiver has no freedom to determine what substance of information he will hear.
Conventional radio broadcasts also have the following problems:
(1) Nobody can select and hear only the information he or she requires. For example, a stock price of a certain company in the stock market cannot be heard at an arbitary time.
(2) A radio receiver set receives an electric wave and converts it to voice without time delay, time shrinkage or time expansion. Thus, one must hear the radio in accordance with the broadcasted program.
(3) One frequency of carrier wave cannot be shared in time (e.g., each frequeny being transmitted several tens of seconds) with plural radio stations, because each radio station must continuously use its assigned frequency at all times.